DE2630585B2 - Catalysts for the polymerization of α-olefins with 2 to 6 carbon atoms and their use for the polymerization of α-olefins with 2 to 6 carbon atoms - Google Patents

Description

or

O> (D

OD

wherein in the 2- and 6-position of the structure (I) and in the 2-position and optionally also in the 8-position in the structure (II) radicals are present, of which at least one is able to exert a stronger steric hindrance than the group - C ₂ Hs, and is a branched alkyl radical with 3 or more carbon atoms, while the other is an alkyl radical or a phenyl radical, and in which alkyl, aryl and alkylaryl radicals can be present as substituents in the other positions,
to which an electron donor compound is optionally partially bound in a complex, with
B) a compound of titanium, vanadium or

Zirconium.
2. Catalysts according to claim 1, characterized

characterized in that the compound B) is a complex the general formula

M _ra M'X _2m Y ■ η E

is where

M Mg, Mn and / or Ca,

m is a number from 0.5 to 2,

M 'Ti, V and / or Zr,

X Cl, Br or J,

Y one or more identical or different atoms or identical or different groups, namely halogen atoms, halogen atoms and at the same time oxygen atoms, - NR2, --OR, -SR,

O
-OC-R

O
- OS-R

O
where R is an alkali. Arvlrest. Cvcloalkvlrest

or aralkyl

Acetylacetonate ions, acetylacetonate ions and at the same time oxygen atoms, the groups or atoms Y in such an amount exist that the valence of M 'is sufficient,

η is a number from 0.5-m to 20-m and

E an electron donor compound from the following classes of compounds:

a) Esters of organic carboxylic acids

b) alcohols,

c) ether,

d) amines,

e) carbonic acid ester,

f) Niltrileund

g) esters of phosphoric acid and phosphorous acid and phosphorus oxychloride

is

3. Catalysts according to claim 1, characterized in that the compound (B) contains titanium, vanadium or zirconium, magnesium and a halogen from the group consisting of bromine and chlorine and a surface area of more than 3 m ² / g or an X-ray spectrum with an halo has, whose intensity maximum is in cases in which chlorine is present in the catalyst component in a Cl / Mg ratio of 1 or more than 1, at a lattice spacing d) between 2.43 and 3.20 Å and in cases in which Bromine is present in a Br / Mg ratio of 1 or more than 1, with a lattice spacing d) between 2.80 and 3.25 Å.

4. Use of the catalysts according to claim 1 to 3 for the polymerization of «-olefins with 2 up to 6 carbon atoms.

5. Use according to claim 3 for the Polymerization in the gas phase.

The polymerization of «-olefins with catalysts made from salts of transition metals and organometallic compounds of elements of the I., II. and III. Group of the periodic table, preferably Aluminum compounds to be obtained is known.

It is also known to use "-olefins" with catalysts made from organometallic compounds of elements of I., II. And III. Group of the periodic table, preferably aluminum, and have been prepared from the reaction product of titanium compounds and magnesium compounds to polymerize with very high yields.
The organometallic aluminum compounds used in these polymerizations are aluminum trialkyls and dialkyl aluminum halides. In particular when using aluminum trialkyls, however, there is the disadvantage of their flammability.

The use of organoaluminum compounds

Bo fertilizers of the type R ₂ AlOR 'or RAI (OR') ₂ as catalyst components, ie of compounds that are non-flammable and therefore less dangerous to handle than aluminum nitrialkyls, has also already been described in general. The catalysts that

b5 contain compounds such as R ₂ AlOR 'organometallic components, but are inactive or have only at high temperatures, which are in any case above 10O ⁰ C, a very low activity

Examples of these are organometallic compounds of aluminum, in which in the above formula R 'is an alkyl radical, e.g. B. a Methyl radical, ethyl radical or propyl radical or an aryl radical, z. B. a phenyl radical, is The compounds of the type RA1 (OR ') 2 lead to catalysts that even at high Temperatures are largely inactive.

It has now surprisingly been found that by suitable choice of a radical R "it is possible _{to obtain compounds of the type R 2} AlOR" and / or RA1 (OR ") ₂ which, by reaction with compounds of transition metals, form catalysts which in the Polymerization of et-olefins having 2 to 6 carbon atoms have an activity similar to that shown by aluminum trialkyls at the temperatures customarily used in industrial processes.

The invention thus relates to the catalysts and their use in the polymerization of «-olefins having 2 to 6 carbon atoms, as described in the claims.

As radicals with greater steric hindrance in component (A) of the catalysts according to the invention are 1-C3H7, tert-QHs, 1-C4-H9, isoamyl and neopentyl to be mentioned, while the other radical is in the 2 or 6 position of the formula I or the 2 or 8 position of the Formula (II) e.g. B. a methyl radical, ethyl radical or propyl radical, or a phenyl radical.

The compounds R ₂ AlOR "can be prepared by known processes, starting from compounds of the formula jo AIR3 and R" 0H, which are generally reacted according to the following reaction:

AlR ₃ + R "0H

R ₂ AlOR "+ RH

This reaction can conveniently be carried out in a hydrocarbon serving as a solvent at room temperature or at an elevated temperature.

According to another process for the preparation of compounds R ₂ AlOR ", AIR ₃ is reacted with A1 (OR") ₃ according to the following stoichiometry:

35

40

2AlR ₃ + A1 (OR ") ₃

3R ₂ AIOR "

45

In this case too, the work is carried out at room temperature or at an elevated temperature.

The compounds of the type RA1 (OR ") ₂ can also be prepared by the following known processes according to one of the following reactions:

I) AIR ₃ + 2 R "OH -

2) R ₂ AlOR "+ R" 0H

3) AlR ₃ + 2AI (OR ") ₃

RA1 (OR ") ₂ + 2RH ■> RA1 (OR") ₂ + RH W -> 3RAI (OR ") ₂

This is done at room temperature or above. _b0

The catalysts of the invention are suitable for the polymerization of, for example, propylene, 1-butene and 1-methylpentene-1. In the polymerization of propylene, the organoaluminum compounds of the aforementioned type R ₂ AI (OR ") and t, -> RA1 (OR") ₂ to increase the stereospecificity of the catalyst can partially with electron donor compounds of the type, for example in the IT-PS 9 32 438 of the applicant is described, are bound in a complex.

The components (B) of the catalysts according to the invention can consist of the halogenated titanium compounds TiCl _{4 , TiBr 4} , 3 TiCl ₃ - AlCl ₃ and halogen alcoholates of titanium from titanium alcoholates, as well as the vanadium or zirconium _{halides VCI 4} , VOCl ₃ and ZrCl ₄ .

Component (B) of the inventive catalysts described in claim 3 can be prepared by various processes. A method is preferred in which a mixture of a titanium, vanadium or zirconium compound and anhydrous magnesium chloride or bromide is ground at least until the surface area is greater than 3 m ² / g or up to in; X-ray diffraction spectrum of the ground product an atrium appears, the intensity maximum of which is in one of the ranges mentioned in claim 3.

According to another method, these catalyst components, which contain titanium, vanadium or zirconium, magnesium and the halogen, can be prepared by reacting a liquid halogenated compound of the transition metal with an oxygen-containing magnesium compound, e.g. B. MgO, Mg (OH) Cl, Magnesiumcarbonai and MgX (OR), in which X is a halogen and R is an alkyl radical or the aryl radical with 1 to 15 carbon atoms. The reaction may be one serving as diluent an inert hydrocarbon at a temperature which is generally in the range of 20 to 150 ⁰ C in the presence or absence can be performed.

The compound (B) of the catalyst according to the invention can also be prepared by reacting a liquid halogenated compound of the transition metal with a magnesium complex of the type MgX ₂ · η D, where X is chlorine or bromine, D is a molecule of water, an alcohol or an electron donor compound, for example from the is made up of ethers, amines, esters, nitriles and other analogous compounds. In this case, the reaction is carried out in the presence of an excess of the transition metal compound.

_{Halogenated compounds of titanium, vanadium or zirconium, in particular TiCl 3} , TiCl ₄ , VCI ₄ , VOCI ₃ , halogen alcoholates of titanium and ZrCl ₄ are used to produce components (B) of the catalysts according to the invention.

The use of compounds of the type R ₂ AIOR "or RAI (OR") ₂ in the preparation of the catalysts according to the invention has the following advantages over the use of aluminum tralkylenes:

1) The aluminum compounds used to prepare the catalysts of the invention are less reactive with oxygen than aluminum trialkyls and are therefore less dangerous, because, unlike aluminum trialkyls, they are not flammable.

2) The compound R "OH, which is preferably used for the preparation of component (A) of the invention Catalysts used can be a phenolic antioxidant of the type shown in im generally as an additive to the polymer after it has been dried and before it is shaped (Extrusion, granulation) is given. The use of the catalysts of the invention hfi Her Olpfirmnlvmpricfltirtn prmntrlirht innicr **

Contact of the polymer with the additive, so that this fully its stabilizing effect can exercise.

3) In today's plants for the polymerization of olefins, the endeavor already exists during the polymerizate in the form of spherical or spheroidal particles to the polymerization that can be used immediately by the customers, so that the costly Drawing and granulating is avoided. In this case, however, it is quite difficult to find such an intimate one Mixing the stabilizer with the polymer to achieve that satisfactory Stabilization is achieved.

When using a compound of the aforementioned type R ₂ AIOR "or RA1 (OR") 2 as the organometallic component of the catalyst according to the invention, the compound R "OH, which is formed by hydrolysis of the organoaluminum compound, remains at the end of the polymerization when the catalyst is deactivated, for example with steam has been formed, in intimate mixture with the polymer, so that it can fully exert its stabilizing effect.

4) In the polymerization of olefins in the gas phase, which is generally carried out in the fluidized bed, it is absolutely necessary to pass a strong stream of olefins several times through the fluidized bed in order to dissipate the heat of reaction and to achieve a good fluidized state. It becomes necessary to constantly replace the organoaluminum compounds which take part in the catalysis and have a generally not insignificant vapor pressure at the polymerization temperature, since these compounds are entrained by the stream of carrier gas.
The accumulation of organoaluminum compounds in the gas cycle also poses a risk due to their flammability. By using the organometallic compounds of the type R ₂ AIOR "or RAI (OR") ₂ these disadvantages are completely eliminated, since these compounds are generally in the solid state and have a practically negligible vapor pressure.

5) Finally, by using the solid organometallic compounds of aluminum of the type R ₂ AlOR "or RA1 (OR") ₂ during the polymerization of olefins in the gas phase, the caking of the polymer particles as a result of the stickiness caused by the presence of the commonly used Aluminum alkyl compounds, which are liquid under the polymerization conditions, is triggered, prevented.

The polymerization of -olefins having 2 to 6 carbon atoms with the _{catalysts according to the invention prepared from compounds of the type R 2} AIOR "or. RA1 (OR") ₂ is generally carried out by known processes, with in the gas phase or in the liquid phase in The presence or absence of an inert hydrocarbon serving as a diluent is carried out.

The polymerization temperature is generally between O and 12O ⁰ C, preferably between 50 and 90 ° C. The Al / transition metal ratio can be in a certain range, but a ratio of 5 to 100,000 is preferably used.

example 1

14 ml of Al (C ₂ Hs) ₃ (100 mmol) were dissolved in 25 ml of anhydrous, degassed n-heptane. A solution of

ί 22 g (100 mmol) of BHT (2,6-di-tert-butyl-p-cresol) was obtained solution in 2 hours zugetropft- The mixture was then maintained until the completion of the reaction at 90 ⁰ C with a 1 molar solution of (C ₂ H ₅ ) 2-Al- (2,6-Ditert.-buty!) - p-cresoxy =

ίο [(C ₂ H ₅ ) ₂ A1DBC] was obtained. 22.6 mg of a catalyst component obtained by dry grinding CI3T1OCH3 and anhydrous MgCl _{2 together} in a ball mill with steel balls in such a proportion that the titanium content was 5.3% by weight and in such a way that the component was X-ray analysis had produced a spectrum with a halo with an intensity maximum at a lattice spacing between 2.43 and 3.20 Å, were desulfurized together with 8 ml of the above-mentioned solution containing the aluminum compound and together with 1000 ml of anhydrous n-heptane was introduced into a stainless steel polymerization autoclave, which had a capacity of 3 l, was equipped with an anchor stirrer and heated to 85 ° C. Then hydrogen (7 atm.) And ethylene (6 atm.) Were added up to a total pressure of 13 atm. introduced, which was kept constant during the polymerization by constant pressure of ethylene. the

The polymerization was terminated after 4 hours. The polymer obtained was filtered off and dried, with 230 g of polyethylene (194,000 g of polymer / g Titanium) with an intrinsic viscosity of 1.6 dl / g.

Comparative experiment A

The experiment was repeated using 18 mg of catalyst component (which contained titanium and magnesium) and a solution of 8 mmol (C ₂ Hs) ₂ AlOCsHs in n-heptane as cocatalyst.

In this case only traces of polyethylene were obtained. This is proof that catalyst _{components of the type R 2} AIOR ", in which R" is a phenyl radical which does not contain any substituents in the 2- and / or 6-position which are more sterically hindered than - C2H5, are practically inactive.

Example 2

The experiment described in Example 1 was repeated using 24 mg of a catalyst component prepared by dry grinding together TiCU and anhydrous MgCl ₂ in a ball mill with steel balls in a ratio such that the titanium content was 3.9% by weight had been. In this way, 390 g of polyethylene (420,000 g of polymer / g of titanium) with an intrinsic viscosity of 1.55 dl / g were obtained.

Example 3

and Comparative Experiments B and C

The experiment described in Example 2 was carried out using 9.4 mg of catalyst component and _b5 starting from a gas mixture of 9 atm. Ethylene and 4 atm. Hydrogen repeated. This gave 280 g of polyethylene (760,000 g of polymer / g of titanium) with an intrinsic viscosity of 2.55 dl / g. To the

Comparison was made of a compound of the type "in which R" represents a group of the formula

CH,

(2,6-Dimethylphenyl) is produced as a cocatalyst. For this purpose, a solution of 1.22 g in 2,6-dimethylphenol (10 mmol) in 20 ml of n-heptane was added dropwise to 1.4 ml of Al (C2Hs) 3 (10 mmol). The mixture was then heated until the completion of the reaction to 8O ⁰ C. The above-described polymerization experiment (Example 3) was then repeated using 20 mg of catalyst component (which contained titanium and magnesium) and the above-mentioned solution of the compound R2AIOR ". In this case, however, only 2 g of polyethylene were obtained (comparative experiment B).: n

In a further comparative experiment C, a compound of the type (C ₂ Hs) ₂ AIOR ", in which R" stands for

(2-tert-butylphenyl) produced as a cocatalyst. For this purpose, 1.53 ml (10 mmol) of 2-tert-butylphenol, which had been diluted to 20 ml with n-heptane, was added dropwise to 1.4 ml of A1 (C ₂ H ₅ ) 3 (10 mmol). The mixture was then maintained until the completion of the reaction at 8O ⁰ C. The above-described polymerization experiment (Example 3) was repeated using 16 mg of catalyst component (which contained titanium and magnesium) and the above-mentioned solution of the compound R2AIOR ". Only 3.5 g of polyethylene were obtained.

These two comparative tests clearly confirm that the catalysts are practically ineffective with Compounds R2AIOR "are obtained in whose radical R" of the formula

no substituent group in the 2- and / or 6-position is present, which is more sterically hindered than the group —C2H3, or not both positions 2 and 6 are substituted.

Example 4

99.4 mg of a catalyst component, prepared by dry co-grinding of TiCU ethyl benzoate and anhydrous MgCl ₂ in such a ω quantity ratio that the titanium content was 5% by weight, and in such a way that the component in the X-ray analysis showed a spectrum similar to that of the catalyst component prepared according to Example 1, together with 6 ml of the solution of (C ₂ Hs) ₂ Al (DBC) prepared according to Example 1 and with 350 ml of desulphurized anhydrous n-heptane were placed in a polymerization autoclave consisting of stainless steel consisted, a capacity of 1000 ml was equipped with a anchor stirrer and was heated to 6O ⁰ C. and to the previous 0.15 atm. Hydrogen had been injected. Then propylene was applied to the autoclave up to a total pressure of 5 atm. pressed on. This pressure was kept constant by continuously pushing in propylene during the duration of the polymerization. The polymerization was terminated after 2.5 hours. The resulting polypropylene was isolated by treatment with methanol and acetone. It weighed 435 g (88,000 g polymer / g titanium). It had an intrinsic viscosity of 1.67 dl / g and a residue of 54.5% on extraction with boiling heptane (36 hours in a Kumagawa extractor).

Example 5

6 ml of the solution of (C ₂ H ₅ ^ Al (DBC) prepared according to Example 1 were diluted to 50 ml with n-heptane and reacted with 162 mg of ethyl p-anisate for 10 minutes at 25 ° C. Using 97 g the same catalyst component as in Example 4 (containing titanium and magnesium) and the solution of (C2H5) 2A1 (DBC) as cocatalyst were, after 5 hours of polymerization under the conditions mentioned in Example 4, 105 g of polypropylene (22,000 g of polymer / g of titanium) an intrinsic viscosity of 2.13 dl / g and a residue on extraction with heptane of 89.6%.

Example 6

A solution of 11 g (50 mmol) of BHT (2,6-di-tert-butyl-p-cresol) in 60 ml of anhydrous, degassed n-heptane was added dropwise over 2 hours to 12.6 ml (50 mmol) of Al (JSO -C ₄ H ₉ ) J given. The mixture was maintained until the completion of the reaction at 9O ⁰ C. A 0.8 molar solution of (iso-C ₄ H _{9 I 2} Al (DBC) was obtained. The experiment described in Example 4 was carried out using 47.4 mg of the catalyst component (containing titanium and magnesium) and 7 ml of the solution compound (iso-C ₄ H ₉₎ 2 Al (DBC) as the cocatalyst. After Sstündiger polymerization at 8O ⁰ C 61 g of polypropylene (26,000 g polymer / g titanium) with an intrinsic viscosity of 1.11 dl / g and were Residue obtained during extraction with heptane of 70.5%.

Example 7

In a 3000 ml stainless steel autoclave, which was equipped with an anchor stirrer, about 50 g of well-dried polypropylene in powder form together with 5 mg of a catalyst _{component obtained by dry grinding together TiCl 4} and anhydrous MgCb in such The quantitative ratio that the titanium content was 3.9% by weight had been prepared, as well as with a solution of 8 mmol (C2H ₅ ) 2A1 (DBC) prepared according to Example 1 and diluted to 50 ml with n-heptane. After evaporation of the solvent by heating to 80 ° C, 0.5 atm. Hydrogen and ethylene on the autoclave up to a total pressure of 15 atm. pressed on. The pressure was kept constant for the duration of the polymerization by constantly pushing in ethylene. The polymerization was terminated after 2 hours. The product obtained was 100 g of polyethylene (500,000 g of polymer / g of titanium).

Example 8

1.39 ml (10 mmol) of Al (C ₂ Hs) _{3 were} dissolved in 22 ml of anhydrous, degassed n-heptane. A solution of 1.78 g (10 mmol) of 2-tert-butyl-4,6-dimethylphenol was added dropwise to the solution over a period of 1 hour. The mixture was then maintained until the completion of the reaction at 8O ⁰ C.

The experiment described in Example 3 was carried out using 20 mg of the catalyst component and the solution described as a cocatalyst repeated. 98 g of polyethylene (125,000 g Polymer / g titanium).

Example 9

A solution of 2 g (10 mmoles) of 2,6-di-tert-butylphenol in 50 ml of n-heptane was added dropwise to 1.4 ml (10 mmoles) of AI (C ₂ HsH) containing 20 ml of anhydrous, degassed n-heptane The mixture was kept until the end of the reaction at 80 ^° C. The experiment described in Example 3 was repeated using 21 mg of the catalyst component and the solution described above as cocatalyst. 240 g of polyethylene were obtained (288 000 g polymer / g titanium).

Example 10

A solution of 20 mmol of 2,6-di-tert-butyl-p-cresol in 20 ml of anhydrous degassed heptane was added dropwise to 20 ml of the solution prepared according to Example 1 [containing (C ₂ Hs) ₂ AIDBC)]. The mixture was diluted to 100 ml with n-heptane and kept at 90 ° C. until the reaction was complete. A compound of the type RA1 (DBC) ₂ , in which DBC stands for 2,6-di-tert-butyl-p-cresoxy, was obtained. The experiment described in Example 3 was repeated using 19 mg of the catalyst component and 80 ml of the solution described above as cocatalyst. In this way, 60 g of polyethylene were obtained (81,000 g of polymer / g of titanium).

Claims (1)

Patent claims: 1. Catalysts for the polymerization of α-olefins having 2 to 6 carbon atoms, consisting of from the reaction product of A) an organometallic aluminum compound of the formula R ₂ AlOR " or RAl (OR '% where R stands for alkyl radicals having 1 to 12 carbon atoms and R ″ a radical of the structures